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tl;dr

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• Table of Contents

Visual Disabilities

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sensory disabilities that involve uncorrectable damage/loss of vision in one or both eyes

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Types & interaction with technology

• complete sight loss
  • uses screen readers (common) or braille output (not common)
  • cannot use monitor and mouse as an input device
  • needs audio descriptions for some content to get more context for visuals
• low vision (vision conditions that cannot be corrected by glasses) — macular degeneration; glaucoma; cataracts; diabetic retinopathy
  • uses screenreaders, screen magnifies, high-contrast modes, and monochrome displays
  • uses larger font sizes by default
  • may or may not use assistive technology
• colorblindness — deuteranopia (green deficiency); protanopia (red deficiency); tritanopia (blue deficiency); achromacy (cannot distinguish any color)
  • will not be able to differentiate between some colors on an interface
  • relies on contrast and non-color information (e.g., symbols, images) to use the interface
• nearsightedness, farsightedness, astigmatism

Assistive technologies

• screen readers, speech input, voice output

• keyboard control

• audio descriptions of visual content

• refreshable Braille

• large monitors

• keyboards with larger letters

• high contrast mode

• enlarged views & resized text

• alternate color palettes (can be enabled by software/browser plugins)

Design considerations

• Alternative text or metadata for non-decorative images (relative content) that screen readers can read out loud are available
• The website can be navigated entirely using a keyboard instead of a mouse
• Page structure and content should make sense when read out loud
• Ensure that text is readable and that elements on the webpage has good color contrast
• Check how zooming in affects page structure
  • Avoid putting content on multiple columns
  • Do not use images of text